Sewing mechanism



April 4, 1939. w. H. LEWIN SEWING MECHANISM Filed Dec. 9, 1936 3Sheets-Sheet l I NV E NTOR.

William yi'en r q oGeurin B Y flzo uc 1 MJ ATTORNEYS April 4, 1939. w.H. LEWIN SEWING MECHANISM Filed Dec. 9, 1936 3 Sheets-Sheet 3 INVENTOR.William Kenya .6:

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BY WZOCKJ' ATTORNEY 5 Patented Apr. 4, 1939 UNITED STATES PATENT OFFICESEWING MECHANISM William H. Lcwin, New York, N. Y. Application December9, 1936, Serial No. 114,914

6 Claims. 01. 112-205 My invention relates to a new and improved sewingmechanism.

One of the objects of my invention is to provide a new and improvedsewing machine for making zig-zag stitches in which the needle andlooper operate in afixed path and in invariable timing.

Another object of my invention is to provide an improved machine forthis purpose, said machine having improved means for feeding the work ina generally forward direction, and for reciprocating the work laterallyrelative to the normal line of forward feed, resulting in the productionof zigzag stitches. Y Another object of my invention is to provide a.simple attachment which can be manufactured at low cost and which can beeasily applied to any sewing machine which produces straight stitches,so as to convert said machine into a zig-zag machine. In particular, andwithout limiting the invention, the attachment can be readily applied tothe well-known sewing machine designated in the trade .as Singer 95-40in order to convert said machine to a zig-zag sewing machine.

Another object of my invention is to provide a sewing machine for makingeither 'zig-zag or straight-away stitches, at will, which will have thesame reliability and the same high speed of operation in making zig-zagstitches as the ordinary machine which makes a straight stitch only.

Another object of my invention is to provide an improved feed dog, and anovel combination of feed dog and needle plate, and to provide novel'means for operating the samein unison.

35 While I show the invention as applied to a lock-stitch machine, I donot wish to be limited to any particular type of sewing machine.

Zig-zag sewing machines have been on the market for many years, in whichthe needle-bar, in

4 addition to being vertically reciprocated, was vibrated laterally fromside to side, across the line of feed, asin the Singer 107 W type., Thisnecessitated mounting the sewing-hook or looper in such manner that theplane in which it turned coincided with the plane of lateral vibrationof the needle-bar, that is, said plane was perpendicular to the line offorward feed. In such an arrangement, a distinct loss of efiiciency andspeed was unavoidable, and said lateral motion resulted in'noise,vibration, and the rapid wear of the lateral motion also made itimpossible to secure a constant or uniform adjustment between thesewing-hook and the needle. These disadvantages 55 and otherdisadvantages which are familiar to needle-bar and its relatedmechanism, and this those skilled in the construction and repair ofthese machines, ultimately reduced the speed of operation to about 2200stitches per minute.

However, the ordinary sewing machine in which the needle-bar is notreciprocated laterally, and

in which the sewing-hook-rotates in a plane exactlyparallel to the lineof feed, is capable of producing reliable stitching at speeds of 4000stitches per minute.

According to the invention herein disclosed, I have secured an eflicientand reliable zig-zag stitch at speeds up to 4000 per minute, using theessential parts of a standard sewing machine, and.

without laterally reciprocating the needle-bar or changing the essentialsewing mechanism, which makes this high-speed of operation possiblewithout undue noise, vibration, or rapid wear.

" My invention is shown in connection with the accompanying drawings anddescription.

Fig. 1 is a side elevation of the improved machine. V

Fig. 2 is a bottom plan view of Fig. '1.

Fig. 3 is a detail elevation, partly in section showing the needle plateand feed dog at'the lefthand extreme of their lateral-travel.

Fig. 4 is a view similar to Fig. 3, showing the needle 'plate and feeddog at the right-hand extreme of their lateral travel.

Fig. 5 is an end elevation, taken at the righthand side of Fig. 1. i

Fig, 6 is-a perspective view of a casting which can be connected to theunderside of the bedplate of a standard machine, said casting havingsome of the operating parts of the device mounted therein. I

Fig. 7 isa sectional view, on the line of Fig. 1, showing certaindetails of the feed mechanism. 1 V

Fig, 8. is a detail sectional view, on the line 8-8 of Fig. '7, showingcertain details of the feed mechanism. 1

" Fig. 9 is an end elevation, partially in section,

on the line 99 of Fig. 1, showing certain oi. the connecting means forreciprocating the needle plate laterally.

Fig. 10 is a top plan view on the line l0l0 oi Fig. 1, showing certaindetails of the needle plate,

feed dog, and cover plate.

Fig. 11 is a detail perspective view showing a part of the needle plateand the feed dog.

. Fig. 12 is a detail sectional view on line l2-l2 of Fig. 2. Fig. 13 isa perspective view of the needle plate and its slide-rod extension.

Fig. 14 is a perspective view of part of the feed mechanism in which thedouble-headed arrows X, and Y, and Z denote the various movements of thefeed dog.

Fig. 15 is a detail sectional view of part of the needle plate, showingone of the depending studs and rollers which laterally reciprocate thefeed dog.

The invention is illustrated as embodied in a sewing machine of standardtype and having many standard parts. Since this machine is wellknown onthe market as Singer 95-40, it is unnecessary to state the details ofthose parts thereof which remain unchanged in the invention.

Referring to Fig. 1, said machine has a hollow arm I, bolted to abedplate 2, said arm I carrying a main shaft 3, which is provided witha. balance wheel 4. Main shaft 3 carries a bevel gear 5, meshing in aone-to-one ratio with a bevel gear 5a of the vertical jack shaft 6,which is provided near its lower end with a bevel gear I, meshing in atwo-to-one ratio with the bevel gear Ia of the sewing-hook shaft 8.Shaft 6 is supported near its lower end by an auxiliary bearing 9, whichforms part of the casting Ill, (illustrated separately in Fig. 6). Thatpart of shaft 6 which protrudes through bearing 9, carries another bevelgear II, which meshes in a one-to-two ratio with a bevel gear I2,carried on a short horizontal jack shaft I3, suitably journaled in thebearings Ma. and 4b, (Fig. 2), which forms part of casting I0. Saidcasting I0 is bolted to the underside of the bedplate 2 by means of fourbolts I5, which also serve to attach arm I to the upper side of bedplate2. Shaft I3 also carries a cam l6, of suitable profile, which cooperateswith the forked end I'Ia of 9. connecting-rod I1. Said connecting-rod I1is pivotally connected to a' link I8, as shown in Fig. 2, by means of anadjustable cone-screw I9, and its lock nut I9a.

Said link I8 is pivotally connected to another link 20, by means of anadjustable cone-screw 2|, and its lock nut 2|a. Said link 2|) is rigidlyfastened to a shaft 22, which can be turned a few degrees in eitherdirection, in its bearing 23, by means of a crank arm 24, rigidlyfastened to said shaft 22, in order to adjust said shaft 22 to vary thethrow of the connecting rod H from zero to maximum, thereby determiningthe width of the zig-zag stitches. To enable the operator to make thisadjustment conveniently, crank arm 24 is connected to a thumb-screw 25,by means of an extension arm 26, which is pivotally connected to arm 24by means of a pivot-screw 21, having a lock-nut 27a. The shank of thethumbscrew 25 is threaded into the extension arm 26 through a suitableslot 28, cut inthe hollow arm I and said thumb-screw 25 can be tightenedat any desired setting of shaft 22, so as to hold shaft 22 in any of itsadjusted positions.

Fig, 1 shows rod I! in neutral position and it is shown in Figs. 3 and4, in the position of maximum throw.

Referring to Figs. 1 and 2, connecting-rod I'I terminates at itsleft-hand end in a yoke I'Ib, which is pivotally connected by means of atapered pin 29 to a perforated lug 30 (Fig. 13), which is rigidlyfastened by means of two screws 30a, to the underside of slide-rod 3|,slidably mounted in a suitable guideway (Figs. 9 and 10) milled into thebedplate 2. Said guideway has edges 32.

Said rod 3| has inclined side-edges, and the edges 32 of the guidewayare correspondingly inclined, A clearance hole 33 (Figs. 2 and 10) isalso cut through the bedplate 2, through which the lug 30 protrudes sothat said lug can be connected to the yoke I'Ib by means of said pin 29,whose tapered surface fits snugly in the tapered bore of the lug 30.Said pin 29 is adjustable to allow for wear, by means of its threadedextension 29a and its lock nut 29b (Fig. 12).

-The left-hand end of the slide-rod 3| carries the needle plate N,rigidly fastened thereto by two screws 34, (Fig. 13), so that the needleplate N necessarily partakes of the lateral to-and-fro motion impartedto the slide-rod 3| by means of the reciprocating motion of theconnectingrod I'I.

Figs. 3 and 4 show the respective positions of the novel parts at theends of the left-hand and right-hand lateral movements of the needleplate and feed bar. V

The needle plate N fits in the guideway 35 of the bedplate 2 (Fig. 10),and the assembly is covered by a thin cover plate 36, fastened tobedplate 2 by means of four screws 31, and having an aperture 38, toexpose a. section of the needle plate N containing the elongatedneedle-hole 62, and to expose the rows of teeth F1 and F2 of the feeddog F. These teeth protrude through therespective slots N1 and N2 of theneedle plate N, in order to contact with the under surface of the work,and to feed the work, in the upper position of said feed dog. Thepresser-foot P holds the work down and said presser foot is ofsuiiicient width to allow for the side-to-side movement of the feed dogF.

- Sufficient bearing surface is given the slide-rod 3| in its guideway,so that the needle plate N attached thereto has no appreciable shake, orlost motion, and the latter is therefore given sufficient clearance inthe guideway 35, and beneath the cover plate 36, so as to avoid frictionat these points.

A detachable section 36a of the cover plate 36 is riveted to the movableslide-plate 39 (Fig. 2) slidably mounted in the guideway 35, andyieldingly retained therein by the spring 46,

As shown in Fig. '7, the underside of needle plate N is provided withdownwardly projecting studs 4|a and 4Ib, secured to the needle plate bymeans of screws 42a and 42b. Turnably mounted on these respective studsare rollers 43a and 43b, which register withv notches 44a and 44b,respectively, of the feed dog F. Said rollers are of sufficient depth toallow for the up-and-down movement of the feed dog F, said movementbeing indicated by the double-headed arrow X in Fig. 14. sufiicientlength to allow for the back-and-forth movement of the feed dog F in thedirection of ordinary feed of the material and reverse thereto, asindicated by the double-headed arrow Y. The direction of ordinaryforward feed of the cloth is indicated by arrow W.

As shown in Fig. 14, the feed dog F is rigidly fastened to the feed-bar45, which is integral with the sleeve 45a, which is turnably andslidably mounted on the shaft 46, which is fixed to the crank arms 41aand 41b, integral with the rock shaft 48. There is sufiicient clearancebetween the ends of the sleeve 45a and the adjacent crank arms 41a and41b, to allow for the side-to-side movement of the feed-bar 45, which isindicated by the double-headed arrow Z. Said side-byside movement isimparted to said feed-bar by means of the rollers 43a and 43bof needleplate N cooperating respectively with the notches 44a and 44b of thefeed dog F.

Conventional means are employed to secure Likewise the said notches areof pivotally connected to a rod 5|, which is suitably.

reciprocated from the main shaft 3. The amplitude of its rockingmovement, which determines the length of the switch, is varied from zeroto maximum by conventional means, and is controlled by the operatorthrough the usual thumbscrew 52.

Likewise, the up-and-down movement of the feed dog F is conventionallysecured by means of a crank arm 53, which carries a stud 54, ,on whichroller is mounted. Said roller cooperates with the forked end 4517 ofthe feed-bar 45 (Fig. '7). Crank arm 53 is carried by rock shaft 56(Fig. 2), which is rockably mounted at its ends on adjustable conebearings 51a and 51b, and said shaft 56 is rocked by means of crank arm58, piv otally connected to a rod 59 which is suitably reciprocated fromthe main shaft}. The roller 55 of the crank arm 53 is ,of suflicientlength to allow for the side-to-side movement of the feedbar member 45b,said movement being indicated by double-headed arrow Z (Fig. 14).

The ordinary needle-bans!) moves needle 6|, through the needle-hole 62,and the needle cooperates with the sewing-hook S in the usual manner.The bobbin case, bobbin case base and positioning finger, all of whichare conventional, are not shown.

Referring to Fig. 11, it will be noted that the serrations or teeth ofthe feed dog F are cut at an angle of about 45 degrees relative to thelongitudinal axis A-A and arrow W, so that when feeding the workforwardly and also laterally to.

the left, for instance (referring to Fig. 11), the working edges of therow of teeth F1 will be presented to the work approximately at rightangle to the resultant movement of the work; and when feeding the workforwardly and also laterally to the right, the working edges of the rowof teeth F2 are likewise presented to the work at right angles to theresultant movement of the work.

The operation of the mechanism is as follows:-

The feed-dog F is raised vertically so rows of teeth move upwardlythrough their respective slots in the needle plate to engage the workagainst the yielding pressure of the presser foot. The feed dog nowmoves forwardly (away from the operator), and at the same time theneedle plate is shifted laterally to the right, so as to shift the clothand the feed dog in the same direction. This combination of thesimultaneous forward and lateral movements of the feed dog produces aresultant feeding movement of the work along a line which is inclined tothe right of the longitudinal axis AA, and at an angle which dependsupon the relationship between the setting of the amplitude of thezig-zag stitch and the setting of the length of the straight-awaystitch. At the completion of the forward movement of the feed dog, whichcoincides with the completion of its lateral movement, the feed dog ismoved beneath the level 0f the top of the needle plate, thereby losingcontact with the work. The work is held immovable by the pressure of thepresser foot against the needle plate, which remains stationary whilethe feed dog is now returned in an idle stroke towards the operator in aline parallel to, and to the right of, axis A-A. At the conclusion ofthe return or idle stroke, the feed dog is again that the moved upwardlyto engage the work as before. It is again moved forwardly, but duringthis stroke the simultaneous lateral motion of.the

needle plate and feed dog takes place to the left of line A--A, so thatthe work is given a resultant feeding movement along a line which isinclined to the left of the axis A-A, and at an angle equal to that ofthe line of the first resultant feeding movement. At the completion ofthis simultaneous forward and lateral movement of the feed dog, it isagain lowered beneath the level of the top of the needle plate andit isreturned idly toward the operator, but this time in a line parallel toand to the left of, axis A-A'. The same cycle of movements is repeated.

In thetype ofmachine specifically illustrated herein, the needle-bar hasonly the usual vertical reciprocating movement. However, the attachmentmay be applied to a machine in which the needle bar moves in anydirection. For convenience, the direction in which the work would befed, if the needle plate and feed dog did not have said lateralreciprocating movement, may be designated as the direction ofstraightaway forward feed. The sewing hook or looper is turned or rockedor otherwise moved in a fixed plane. This plane is preferably, but notnecessarily, parallel to said direction of straight-away forward feed.Said plane may be adjusted relative to said direction, but said planedoes not change after adjustment and during the opera tion of themachine. i

The cam l6 has dwell portions which operate t hold the needle plate infixed position, at predetermined intervals, and while the needle is inthe work. While the needle plate is thus held against lateral movement,the feed-dog is moved back in its idle stroke. Hence the lateralmovement of the needle plate is intermittent.

While I have shown a feed-dog, it is to be understood that other typesof feeding devices could be substituted, whenever a feed-dog having afour-motion movement relative to the needleplate, is specified in-anypartthereof, including the claims.

The movement of the feed dog (excepting its lateral to-and-fro movement)may be designated as the usual four-motion movement of the feed dog. Themovement of the feed dog while it is in its upper position may bedesignated as a feeding stroke, and the movement of the feed dog whileit is in its lower position may be designated as Whenever I refer to aneedle plate in the claims. it is to be understood that I wish toinclude any equivalent work-support. It will be noted that the needleplate is connected directly to the feed device, by means of the studs aand llb (including the rollers), and the notches a and b. This directconnection makes it' unnecessary to provide a plurality of cams or thelike, for producing the lateral movement of the needle plate, and thelateral movement of'the feed dog. Likewise and as shown in Fig. 11, theteeth of the feed dog have longitudinal; axes, said axes being inclinedto the longitudinal axis of the feed dog. 1

Likewise, I do not wish to be limited to a feed dog having two separatedrows'of teeth, as I may use a feed dog having a single row of teeth, orhaving more than two rows.

Likewise, the invention can be applied to a machine having one or moreneedles, and it can be used with embroidery machines.

In the embodiment specifically illustrated, the needle-bar has areciprocating movement in the direction of its longitudinal axis, andthis movement, for convenience, is designated as a verticalreciprocating movement. However, it would not be-departing from theinvention if the needlebar had a movement or movements in addition tosaid reciprocating movement, or if the needle- 'ment of the needle platebeing at an angle to the direction of movement of the needle, a movablefeed device, operating mechanism adapted and operative to actuate theneedle to-and-fro and to move the needle plate to-and-fro and to imparta four-motion movement of the feed device relative to the needle plate,direct connecting means between said needle plate and said feed deviceso that the feed device is moved to-and-fro in unison with theto-and-fro movement of the needle plate, said operating mechanism beingoperative and timed to move the feed device forwardly in a feedingstroke and simultaneously to move the needle plate and the feed devicelaterally in one direction, then to move the feed device rearwardly inan idle stroke while the needle plate is held against substantialmovement, then to move the feed device forwardly in a feeding strokewhile the needle plate and the feed device are moved in a seconddirection which is opposite to the first-mentioned direction, and thento move the feed device rearwardly in an idle stroke while,

the needle plate is held against substantial movement.

2. A sewing machine having a needle mounted for to-and-fro movement in adirection which makes an angle'with a horizontal plane, a needle platemounted for to-and-fro movement in a horizontal plane, a movable feeddevice, said feed device being movable forwardly and rearwardly andvertically up-and-down relative to the needle plate, means directlyconnecting said needle plate and said feed device for simultaneousto-and-fro movement, when the needle plate is moved toand-fro.

.3. A sewing machine having a needle bar mounted for verticalreciprocating movement, a needle plate mounted for reciprocating lateralmovement in a horizontal plane, a feed dog hav'- ing teeth which arelocated to project through an open portion of 'the needle plate, saidfeed dog being movable forwardly and rearwardly and verticallyup-and-down relative to the needle plate, means connecting said needleplate and J said feed dog for simultaneous lateral movement, said teethof said feed dog having longitudinal axes which are inclined relative tothe longitudinal axis of the feed dog. Y

4. A sewing machine having a needle bar actuated by a main shaft forvertical reciprocating movement, a needle plate mounted for lateralreciprocating movement in a horizontal plane, a feed dog having teethwhich are located to project through an open part of said plate, saidsewing machine having a bed plate, a bearing device connected to theunderside of said bed plate, a first vertical shaft connected to saidmain shaft and having the lower end thereof supported in said bearingdevice, a second and horizontal shaft supported in said bearing device,intermeshing gears connecting said first shaft and said second shaft, alink driven from said second shaft and connected to the needle plate andreciprocating the needle plate intermittentlyand laterally, meansadapted to regulate the amplitude of lateral movement of said needleplate, said feed dog having longitudinal notches, said needle platehaving depending members which are located in said notches so that thefeed dog is moved laterally in unison with the needle plate, andsupplemental mechanism adapted to impart a four-motion movement to saidfeed dog relative to said needle plate.

5. In a sewing machine, the sub-combination of a needle plate mountedfor lateral reciprocating movement in a horizontal plane, said needleplate having an open part, a feed dog mounted for four-motion movementand having teeth which are located to project through said open partduring part of the four-motion movement of said feed dog, mechanismoperative to impart said four-motion movement to the feed dog, saidneedle plate having depending lugs which are located in correspondingrecesses of the feed dog, so that the feed dog is also moved in unisonwith said lateral reciprocating movement of the needle plate.

6. A sewing machine having a bed plate, a bearing device connected tothe underside of said bed plate, said sewing machine having a mainshaft, 2. first vertical jack-shaft, gears connecting said main shaftand said first vertical jack-shaft in a first ratio, the bottom end ofsaid first jackshaft extending below said bed plate and being supportedin said bearing device, a second jackshaft supported in said bearingdevice below the work plate, gears connecting said first jack-shaft tosaid second jack-shaft in a second ratio which is lower than the firstratio, a link driven from the second jack-shaft, a needle plate mountedfor lateral reciprocating movement in a horizontal plane and connectedto and driven intermittently in said movement by said link, a

hook mounted on a hook-shaft, the first jackshaft being connected bygears to the hook shaft in a third ratio which is higher than the firstratio, a needle mounted for vertical reciprocating movement, said hookbeing mounted for turning a predetermined plane, said needle platehaving an open part, a feed dog mounted for fourmotion movement relativeto the needle plate and having teeth located so that they projectthrough said open part during part of the four-motion movement of saidfeed dog,mechanism adapted and operative to impart said four-motionmovement to the feed dog, said needle plate having depending lugs whichare located in longitudinal recesses of the feed dog so that said feeddog is moved laterally in unison with the lateral reciprocating movementof the needle plate, the operating mechanism for the needle plate and ina second direction which is opposite to the first-mentioned direction,and then to move the feed dog rearwardly in a lower idle stroke whilethe needle plate is held against substantial lateral movement, andmechanism for regulating the stroke of said link, said mechanismincluding an additional jack-shaft which is mounted below the bed platein said bearing member,

